Objective: To explore the relationship between vascular subcortical encephalopathy, ventricular dilation and clinical severity in idiopathic normal pressure hydrocephalus (iNPH).

Background: The frequent co-occurrence of iNPH and vascular white matter lesions (WML) has been well described in previous literature. Although the clinical impact of WML on iNPH severity is generally acknowledged, the relation between these two conditions is still under investigation.

Method: 52 consecutive patients (33 males, aged 77,7 +/-4) diagnosed with iNPH following the International NPH Consultant Group Guidelines were enrolled from our Movement Disorders clinic. Clinical history concerning cardiovascular risk factors was collected for each subject. Participants underwent complete neurologic evaluation, coupled with standardized motor (iNPH gait and balance scales) and cognitive (MMSE and MoCA test) assessment, and 3 Tesla brain MRI for standardized measurement of WML and NPH (Fazekas scale, Evans’ index). Subjects were subsequently divided into two groups, depending on radiological severity of vascular disease: Group 1 (23 subjects, Fazekas score 5-6, corresponding to moderate/severe vascular involvement), and Group 2 (22 subjects, Fazekas score 0-4, absent/mild vascular involvement).

Results: Statistical analysis revealed a significant correlation between motor and cognitive performance (p=0.028, R=0.31), no correlation between ventriculomegaly (evaluated through Evans’ index – EI) and WML, no association between EI and disease severity. Patients with moderate/severe vascular disease showed worse cognitive and motor performance than patients with mild or absent vascular involvement (p=0.013 and p=0.02 for cognitive and motor performances, respectively), despite no evidence of different prevalence of cardiovascular risk factors.

Conclusion: Our study confirms the role of vascular white matter disease as a major determinant of both motor and cognitive impairment severity in patients with iNPH. The degree of vascular involvement is not entirely related to cardiovascular risk factors, suggesting a specific etiology, directly related to iNPH. As WML does not correlate with EI values, more complex hypotheses than plain mechanical compression should be taken into consideration in future studies, possibly involving the glymphatic system.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/vascular-white-matter-involvement-in-idiopathic-normal-pressure-hydrocephalus-association-with-cognitive-and-motor-impairment/